Small-Incision Lenticule Extraction: Laser Energy and Vision Recovery Analysis
Purpose
To compare visual and refractive outcomes according to the laser energy used during small-incision lenticule extraction (SMILE).
Methods
Prospective, non randomized study. Each patient was treated by SMILE. This study enrolled 362 eyes of 184 patients (mean age at surgery 30 years ± 6.12(SD)) with myopia or myopic astigmatism -4.19 ± 2.12 diopters (D). Two groups were formed based on the laser energy used: group 1: high energy (34 to 38) and group 2: low energy (24 to 34). Before surgery, 1 week and 1 and 3 months after surgery we assessed the manifest refraction, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), topography, aberrometry, keratometry, pachymetry. We checked that there were no statistically significant differences in preoperative data (MRSE, cylinder, Km, pachymetry, topography, aberrometry and MTF) between two groups (p > .05).
Results
Snellen (20/) uncorrected distance visual acuity (UDVA), at 1 and 3 months postoperatively, were, respectively, 23.00±8.04 and 22.27±11,22 in group 1 and 20.00±4.07 and 18,56 ±10,54 in group 2 (p<.05). At 1 and 3 month postoperatively, respectively, 55,78% and 67,07% achieved corrected distance visual acuity monocular of 20/20 or better in group 1 and 82% and 88,46% in group 2 (p<.05). At 1 and 3 months, respectively, 5 and 2 eyes lost one or more line of visual acuity in group 1. Whereas eyes of group 2 had an unchanged or gain one or more of corrected distance visual acuity (p<.05). The MTF values and aberration analysis were significantly better in group 2 than in group 1 at 1 (p<.05) and 3 (p<.05) months of follow-up.
Conclusion
Small-incision lenticule extraction (SMILE) is a safe and effective procedure. Using the lower laser energy results in better and faster vision recovery.